Use of 1-hydroxy-2-pyridones for treating mucosa diseases which are difficult to treat

ABSTRACT

The compound of the formula I                    
     is suitable for the preparation of pharmaceuticals for the treatment of fungal disorders caused by azole-resistant fungi.

The number of mucosal disorders which are difficult to treat has considerably increased in recent times, and the increasing trend continues. The mucosal disorders which are difficult to treat nowadays include primarily candidoses of the oral and vaginal mucosa.

Candidoses are defined as infections usually caused by Candida albicans, but also by a large number of other Candida species which grow opportunistically (C. krusei, C. tropicalis, Candida glabrata and many others). The yeast-like fungi which are often present anyway in the oral cavity, the gastrointestinal tract and the vagina grow under particular conditions and assume parasitic/pathogenic characteristics. Yeast-like fungi are able in some circumstances to colonize the skin and its appendages, all mucosae near the skin and several internal organs (esophagus, lung etc.) and, in this event, induce a remarkably wide range of disorders.

The occurrence of a candidosis may be favored in particular by pregnancy, metabolic disorders, infectious diseases, tumors and immunodeficiencies. Locally favoring factors are regarded as being mechanical irritation (for example dentures), occlusion, moisture and moist heat.

The occurrence of extensive oral candidosis is nowadays regarded in most countries as one of the principal clinical signs of impaired functioning of the immune system. Persistent oral candidoses indicate in many HIV patients the transition to immunodecompensation. In advanced immunodeficiency there are also erosive, and sometimes ulcerative, inflammations involving the gingiva, and candidal balanitis, candidal vulvitis and Candida-related anal eczema are not uncommon. Intestinal infections and candidal sepsis are likewise observed.

In immunocompetent patients, nystatin is regarded as the agent of choice for local treatment of Candida infections, but clinical experience shows that nystatin therapy on its own is often insufficient in HIV-infected immunodeficient patients. In these cases, systemic therapy with antimycotics of the azole type is widely used. Candida strains resistant to azoles were virtually unknown up to 1989. However, the treatment of vaginal candidoses has often proven difficult due to the occurrence of mixed infections with the protozoal strains Trinchomonas vaginalis and Entamoeba histolytica.

However, since the use of fluconazole for preventing recurrence of oropharyngeal candidoses in HIV patients, the number of azole resistances which have become known has increased dramatically. Up to and including the 1st half of 1995, 98 publications in the specialist literature reported resistance of Candida strains to azoles.

The documents EP 0 241 918 or U.S. Pat. No. 4,797,409 describe the preparation of 1-hydroxy-2-pyridones and their use for controlling mainly infections by fungi and yeast, and pharmaceuticals containing these compounds.

It is therefore an object of the present invention to provide topical pharmaceutical formulations which are suitable for breaking through exsistent intrinsic and acquired resistances of Candida strains to azoles, while simultaneously having activity on the problem organisms Trinchomonas vaginalis and Entamoeba histolytica.

It has now been found that compounds of the formula I are outstandingly suitable for the treatment of candidoses caused by yeast strains with intrinsic and acquired azole resistance. Said compounds are also distinguished by their activity, which is sufficient for therapeutic purposes, on the problem organisms Trinchomonas vaginalis and Entamoeba histolytica which are often the cause of the development of mixed infections in cases of vaginal candidosis.

The invention relates to the use of the compound of the formula I

in which R¹, R² and R³, which are identical or different, are hydrogen atom or alkyl with 1-4 carbon atoms, and R⁴ is a saturated hydrocarbon radical with 6 to 9 carbon atoms or a radical of the formula II

where

X is S or O,

Y is a hydrogen atom or up to 2 halogen atoms such as chlorine and/or bromine,

Z is a single bond or the divalent radicals O, S, —CR₂—(R═H or C₁-C₄-alkyl) or other divalent radicals with 2-10 carbon and, where appropriate, oxygen and/or sulfur atoms linked to form a chain, and—when the radicals contain 2 or more oxygen and/or sulfur atoms—the latter must be separated from one another by at least 2 carbon atoms, and where 2 adjacent carbon atoms can also be linked together by a double bond, and the free valencies of the carbon atoms are saturated by H and/or C₁-C₄ alkyl groups,

Ar is an aromatic ring system which has up to two rings and can be substituted by up to three radicals from the group of fluorine, chlorine, bromine, methoxy, C₁-C₄-alkyl, trifluoromethyl and trifluoromethoxy,

for the preparation of a pharmaceutical for the treatment of fungal disorders caused by azole-resistant fungi.

The compounds according to the invention are furthermore suitable for the treatment of trichomoniasis, one of the commonest causes, which is spread around the world, of non-gonorrheal urethritis. The disorder is caused by the pathogen Trinchomonas vaginalis which is one of the protozoa.

The carbon chain members in the “Z” radicals are preferably CH₂ groups. If the CH₂ groups are substituted by C₁-C₄-alkyl groups, CH₃ and C₂H₅ are preferred substituents.

Examples of “Z” radicals are:

—O—, —S—, —CH₂—, —(CH₂)_(m)—(m=2-10), —C(CH₃)₂—, —CH₂O—, —OCH₂—, —CH₂S—,

—S CH₂—, —S CH (C₂H₅)—, —CH═CH—CH₂O—, —O—CH₂—CH═CH—CH₂O—, —O CH₂—

CH₂O—, —O CH₂—CH₂CH₂O—, —S CH₂ CH₂ CH₂ S—, —S CH₂ CH₂ CH₂ CH₂

—O—, —S CH₂ CH₂ O CH₂ CH₂ O—, —S CH₂CH₂ O CH₂ CH₂ O—CH₂ CH₂ S—, or —S—CH₂—C (CH₃)₂—CH₂—S—.

The radical “S” is a sulfur atom, and the radical “O” is an oxygen atom. The term “Ar” means phenyl and condensed systems such as naphthyl, tetrahydronaphthyl and indenyl, and isolated systems such as those derived from biphenyl, diphenylalkanes, diphenyl ethers and diphenyl thioethers.

Principal representatives of the class of compounds characterized by the formula I are:

6-[4-(4-chlorophenoxy)phenoxymethyl]-1-hydroxy4-methyl-2-pyridone;

6-[4-(2,4-dichlorophenoxy)phenoxymethyl]-1-hydroxy-4-methyl-2-pyridone;

6-(4-biphenylyloxymethyl)-1-hydroxy-4-methyl-2-pyridone;

6-(4-benzylphenoxymethyl)-1-hydroxy-4-methyl-2-pyridone;

6-[4-(2,4-dichlorobenzyloxy)phenoxymethyl]-1-hydroxy-4-methyl-2-pyridone;

6-[4-(4-chlorophenoxy)phenoxymethyl]-1-hydroxy-3,4-dimethyl-2-pyridone;

6-[4-(2,4-dichlorobenzyl)phenoxymethyl]-1-hydroxy-3,4-dimethyl-2-pyridone;

6-[4-(cinnamyloxy)phenoxymethyl]-1-hydroxy4-methyl-2-pyridone;

1-hydroxy-4-methyl-6-[4-(4-trifluoromethylphenoxy)phenoxymethyl]-2-pyridone;

1-hydroxy4-methyl-6-cyclohexyl-2-pyridone

or

1-hydroxy4-methyl-6-(2,4,4-trimethylpentyl)-2-pyridone.

The abovementioned compounds of the formula I can be employed both in free form and in the form of salts, and use in free form is preferred. The compounds of the formula I to be employed in the formulations can be prepared, for example, by processes disclosed in U.S. Pat. Nos. 2,540,218 or 4,797,409.

The term “azole-resistant fungi” means all species of fungi or yeasts which have become resistant to antimycotics, for example to antimycotics which contain azole residues, such as fluconazole.

Immunosuppressed patients are preferably treated such as diabetics, asthmatics, smokers, AIDS patients, patients before and after transplants, cancer patients, patients chronically treated with antibiotics, cytostatics or corticosteroids, patients with antimycotic-resistant fungi, in particular patients with fluconazole-resistant fungi or elderly people.

Suitable for the use of said compounds according to the invention are liquid, semisolid and solid pharmaceutical formulations, in particular solutions, cream, ointment and gel formulations, and pastilles and pessaries.

The active substance is incorporated into the formulations according to the invention in amounts which are normally between about 0.05 and about 5%, preferably between 0.1 and 1%.

Topical treatment of candidoses caused by yeast strains with intrinsic and acquired azole resistance with the pharmaceuticals according to the invention is able to achieve an effective cure.

The compositions according to the invention can also be employed successfully for the treatment of vaginal candidoses with mixed infections by the protozoal strains Trinchomonas vaginalis and Entamoeba histolytica.

EXAMPLE 1

A formulation according to the invention has the following composition:

6-[4-(4-Chlorophenoxy)phenoxymethyl]-1-hydroxy-4-methyl-  0.50% 2(1H)-pyridone Hydroxyethylcellulose  1.50% Polyethylene glycol 7 glyceryl cocoate  5.00% 1,2-Propylene glycol 10.00% Isopropyl alcohol 20.00% Demineralized water 63.00%

EXAMPLE 2

A formulation according to the invention has the following composition:

6-[4-(4-Chlorophenoxy)phenoxymethyl]-1-hydroxy-4-methyl- 1.00% 2(1H)-pyridone 2-Octyldodecanol 5.00% Liquid paraffin 5.00% Cetyl alcohol 5.00% Stearyl alcohol 5.00% Myristyl alcohol 5.00% Polyoxyethylene 20 sorbitan monostearate 3.00% Sorbitan monostearate 2.00% Demineralized water 69.00% 

EXAMPLE 3

A formulation according to the invention has the following composition:

6-Cyclohexyl-1-hydroxy-4-methyl-2(1H)-pyridone  5 mg Polyethylene glycol 1500 1500 mg  Polyethylene glycol 4000 1000 mg  Polyethylene glycol 6000 165 mg Sodium bicarbonate 180 mg Tartaric acid 150 mg

EXAMPLE 4

A formulation according to the invention has the following composition:

6-[4-(4-Chlorophenoxy)phenoxymethyl]-1-hydroxy-4-methyl-  10 mg 2(1H)-pyridone Tylose C 1000 P  30 mg Polyethylene glycol 6000 500 mg Mannitol 305 mg Sodium stearyl fumarate  5 mg

EXAMPLE 5

Test of Efficacy

Determination of the efficacy of 6-[4-(4-chlorophenoxy)phenoxymethyl]-1-hydroxy4-methyl-2(1H)-pyridone (Compound 1) on fluconazole-resistant strains of Candida albicans

Fluconazole-resistant strains of Candida albicans are isolated from patients who have been treated, for example, with fluconazole for more than one year. For this purpose, samples are taken from the patients' mouths and applied, undiluted or diluted 1:100, to an RPMI 1640 agar (Gibco/BRL, Life Technologies GmbH, D-76339 Eggenstein) which contains about 1.0 μg/ml fluconazole. Resistant Candida albicans strains are isolated, further purified on agar and stored isolated in peptone/dextrose slant agar tubes.

The activity of Compound 1 and fluconazole is determined by the microtiter dilution technique in RPMI 1640 medium. The growth medium RPMI 1640 buffered with 0.165 M morpholinopropanesulfonic acid pH 7.0 is introduced into 96-well microtiter plates. Serial dilutions by a factor of 2 are prepared for Compound 1 and fluconazole to result in final concentrations of 256 to 0.002 μg/ml of Compound 1 and fluconazole. The microtiter plates prepared in this way are incubated with the Candida strains to be tested. For comparison purposes, the two Candida albicans strains ATCC 90028 and 90029 which are not resistant to fluconazole are included in the test. The initial cell count is 1-5 ×10³ colony-forming units per ml of growth medium. The microtiter plates are incubated at 35° C. for 48 hours. The minimum inhibitory concentration is determined by photometry at 510 nm. Table 1 shows the results:

TABLE 1 Minimum inhibitory concentration (MIC) (μg/ml) Strain Fluconazole Compound 1 Candida albicans ATCC 90028 0.5 1 Candida albicans ATCC 90029 1 0.5 Candida albicans 94/3 32 2 Candida albicans 94/14 32 2 Candida albicans 94/57 >256 1 Candida albicans 94/62 >256 1 Candida albicans 94/90 >256 1 Candida albicans 94/118 >256 2 Candida albicans 94/134 >256 1 Candida albicans 94/138 >256 1 Candida albicans 94/222 >256 1 Candida albicans 94/231 >256 1 Candida albicans B6 1 1 Candida albicans B70 >256 1 Candida albicans B75 2 1 Candida krusei B1 32 0.5 Candida krusei B4 16 1 Candida glabrata B12 4 0.5 Candida glabrata B14 2 0.5 Candida glabrata B18 8 0.5 Candida glabrata B21 8 1 Candida glabrata B35 8 1 Candida glabrata B37 16 1 Candida glabrata B38 16 1 Candida glabrata B39 8 0.5 Candida glabrata B40 16 1 Candida glabrata B50 16 0.5 Candida glabrata B51 32 0.5 Candida guillermondii B47 4 1

Table 1 shows that Compound 1 impedes the growth of Candida strains in a very narrow concentration range—irrespective of existent fluconazole resistance.

EXAMPLE 6 In vitro activity of the Compound 1 on protozoa

n = MIC (μg/ml) Trichomonas vaginalis 5 31.2₍₃₎, 125₍₂₎ Entamoeba histolytica 4 31.2, 62.5₍₃₎ n = number of strains investigated; the number given in parentheses corresponds to the number of tested strains with which the stated MIC was determined. 

What is claimed is:
 1. A method for treating a fungal disorder caused by at least one fluconazole-resistant fungus or at least one fluconazole-resistant yeast, or a combination thereof, in a human or animal patient in need of such treatment, comprising topically applying to the patient at least one compound of formula I, at least one pharmaceutically acceptable salt thereof, or a combination of the foregoing:

where R¹, R², and R³, which are identical or different, are H or alkyl having 1 to 4 carbon atoms, and R⁴ is a saturated hydrocarbon radical having 6 to 9 carbon atoms or a radical of formula II:

where: X is S or O; Y is H, or 1 or 2 identical halogen atoms, or a mixture of 2 different halogen atoms; Z is a single bond, or a bivalent radical comprising (1) O, or (2) S, or (3) —CR₂—, where R is H or (C₁-C₄)-alkyl, or (4) from 2 to 10 carbon atoms linked in the form of a chain, which optionally further comprises one or more of the following: (i) a carbon-carbon double bond, or (ii) O, S, or a mixture thereof, wherein if 2 or more O or S atoms or a mixture thereof are present, each O or S atom is separated by at least 2 carbon atoms; and, in any of the foregoing bivalent radicals, free valences of the carbon atoms of said bivalent radical are saturated by H, (C₁-C₄)-alkyl, or a mixture thereof; and Ar is an aromatic ring system having one or two rings which can be substituted by one, two, or three radicals, which may be identical or different, which are halogen, methoxy, (C₁-C₄)-alkyl, trifluoromethyl, or trifluoromethoxy.
 2. A method for treating a fungal disorder caused by at least one fluconazole-resistant fungus or at least one fluconazole-resistant yeast, or a combination thereof, in a human or animal patient in need of such treatment, as claimed in claim 1, in which Ar is phenyl, R¹ and R³ are hydrogen, and R² is methyl.
 3. A method for treating a fungal disorder caused by at least one fluconazole-resistant fungus or at least one fluconazole-resistant yeast, or a combination thereof, in a human or animal patient in need of such treatment, as claimed in claim 1, in which Ar is derived from biphenyl, diphenylalkane, or diphenyl ether.
 4. A method for treating a fungal disorder caused by at least one fluconazole-resistant fungus or at least one fluconazole-resistant yeast, or a combination thereof, in a human or animal patient in need of such treatment, as claimed in claim 1, in which Z is a single bond or O.
 5. A method for treating a fungal disorder caused by at least one fluconazole-resistant fungus or at least one fluconazole-resistant yeast, or a combination thereof, in a human or animal patient in need of such treatment, as claimed in claim 1 in which the at least one compound of formula I comprises 6-[4-(4-chlorophenoxy)-phenoxymethyl]-1-hydroxy-4-methyl-2-pyridone, 1-hydroxy-4-methyl-6-cyclohexyl-2-pyridone, 1-hydroxy-4-methyl-6-(2,4,4-trimethylpentyl )-2-pyridone, at least one pharmaceutically acceptable salt thereof, or a combination of the foregoing.
 6. A method for treating a fungal disorder caused by at least one fluconazole-resistant yeast in a human or animal patient in need of such treatment, as claimed in claim 1 in which the fluconazole-resistant yeast has an intrinsic fluconazole resistance.
 7. A method for treating a fungal disorder caused by at least one fluconazole-resistant yeast in a human or animal patient in need of such treatment, as claimed in claim 1 in which the fluconazole-resistant yeast has an acquired fluconazole resistance.
 8. A method for treating a fungal disorder caused by at least one fluconazole-resistant fungus or at least one fluconazole-resistant yeast, or a combination thereof, in a human or animal patient in need of such treatment, as claimed in claim 1 in which the disorder is vaginal candidoses.
 9. A method for treating a fungal disorder caused by at least one fluconazole-resistant fungus or at least one fluconazole-resistant yeast, or a combination thereof, in a human or animal patient in need of such treatment, as claimed in claim 1 wherein the compound of formula I destroys or inhibits the growth of protozoa from groups Trichomonas or Entamoeba, or a combination thereof.
 10. A method for treating a fungal disorder caused by at least one fluconazole-resistant fungus or at least one fluconazole-resistant yeast, or a combination thereof, in a human or animal patient in need of such treatment, as claimed in claim 1 wherein the compound of formula I destroys or inhibits the growth of Trichomonas vaginitis, Entamoeba hystolytica, or a combination thereof.
 11. A method for treating a fungal disorder caused by at least one fluconazole-resistant fungus or at least one fluconazole-resistant yeast, or a combination thereof, in a human or animal patient in need of such treatment, as claimed in claim 1, in which the fungal disorder affects oral mucosa of the patient.
 12. A method for treating a fungal disorder caused by at least one fluconazole-resistant fungus or at least one fluconazole-resistant yeast, or a combination thereof, in a human or animal patient in need of such treatment, as claimed in claim 1, in which the fungal disorder affects vaginal mucosa of the patient.
 13. A pharmaceutical composition useful for topically treating a fungal disorder caused by at least one fluconazole-resistant fungus or at least one fluconazole-resistant yeast, or a combination thereof, in a human or animal patient in need of such treatment, comprising at least one pharmaceutically acceptable carrier and an efficacious amount of at least one compound of formula I, at least one pharmaceutically acceptable salt thereof, or a combination of the foregoing:

where R¹, R², and R³, which are identical or different, are H or alkyl having 1 to 4 carbon atoms, and R⁴ is a saturated hydrocarbon radical having 6 to 9 carbon atoms or a radical of formula II:

where: X is S or O; Y is H, or 1 or 2 identical halogen atoms, or a mixture of 2 different halogen atoms; Z is a single bond, or a bivalent radical comprising (1) O, or (2) S, or (3) —CR₂—, where R is H or (C₁-C₄)-alkyl, or (4) from 2 to 10 carbon atoms linked in the form of a chain, which optionally further comprises one or more of the following: (i) a carbon-carbon double bond, or (ii) O, S, or a mixture thereof, wherein if 2 or more O or S atoms or a mixture thereof are present, each O or S atom is separated by at least 2 carbon atoms; and, in any of the foregoing bivalent radicals, free valences of the carbon atoms of said bivalent radical are saturated by H, (C₁-C₄)-alkyl, or a mixture thereof; and Ar is an aromatic ring system having one or two rings which can be substituted by one, two, or three radicals, which may be identical or different, which are halogen, methoxy, (C₁-C₄)-alkyl, trifluoromethyl, or trifluoromethoxy. 